The present invention relates to a device and method for determining the contour of a workpiece by combining incomplete data sets to produce a representative of the workpiece contour, wherein the incomplete data sets represent portions of the workpiece contour.
Preferably, a device such as the present invention is used in numerically controlled machine tools. In certain numerically controlled machine tools, the generated workpiece contour is represented on a display screen so that a program of machining instructions for producing the workpiece contour on the numerical machine tool can be checked for accuracy. Corrections to the program, if any, can therefore be made before the workpiece is machined by the tool.
This type of machining system requires a workpiece contour generation program. The data from which the workpiece contours are generated should be, insofar as possible, read directly from the workpiece drawing. A typical workpiece drawing consists of a sequence of juxtaposed straight lines and circular arcs linked to one another to form the contour of the workpiece. If the starting point and the end point of each straight line curve are given in the drawing together with the starting and ending points of the circular arcs, including their centers, the process of obtaining the desired workpiece contour on a numerically controlled machine tool would present no difficulties. In reality however, the geometry of the workpiece is in general not adquately provided in the drawing. The intersection points of the circular arcs with one another and with rectilinear curve parts are generally unknown.
Underlying the present invention is the insight that the great majority of components or workpieces that are produced on numerically controlled machine tools can be constructed from selected geometric forms linked with one another. The number of different contour sections that are needed to be able to define the predominant portion of a typical workpiece is relatively small. These geometric forms can generally be defined by the geometric dimensions of the contour sections.
For the worker in the field, it will be obvious that the number of contour sections and their specific properties can be altered.
If therefore one views the workpiece drawing, it becomes evident that the resulting contour of the workpiece can be described by a series or sequence of contour sections. However, complete geometric data can be taken directly from the workpiece drawing only in the rarest of cases.
It is therefore an object of the present invention to create a device with the aid of which there can be determined a complete workpiece contour from contour sections whose geometric data does not have to be complete.